Sign kerchunk-style reference mappings (#35)

CHANGELOG.md

@@ -1,3 +1,9 @@
+# 0.4.5
+
+## New Features
+
+* `sign` will now sign [Kerchunk](kerchunk)-style dictionaries of references.
+
 # 0.4.4
 
 ## New Features
@@ -49,3 +55,4 @@
 [gh-25]: https://github.com/microsoft/planetary-computer-sdk-for-python/issues/25
 [gh-30]: https://github.com/microsoft/planetary-computer-sdk-for-python/pull/30
 [xarray-assets]: https://github.com/stac-extensions/xarray-assets
+[kerchunk]: https://fsspec.github.io/kerchunk/

planetary_computer/sas.py

@@ -1,6 +1,8 @@
 import re
 from datetime import datetime, timezone
-from typing import Any, Dict, Optional
+from typing import Any, Dict, Optional, Mapping
+import collections.abc
+import copy
 import warnings
 
 from functools import singledispatch
@@ -70,12 +72,13 @@ def sign(obj: Any) -> Any:
 
     Args:
         obj (Any): The object to sign. Must be one of:
-            str (URL), Asset, Item, ItemCollection, or ItemSearch
+            str (URL), Asset, Item, ItemCollection, or ItemSearch, or a mapping.
     Returns:
         Any: A copy of the object where all relevant URLs have been signed
     """
     raise TypeError(
-        "Invalid type, must be one of: str, Asset, Item, ItemCollection, or ItemSearch"
+        "Invalid type, must be one of: str, Asset, Item, ItemCollection, "
+        "ItemSearch, or mapping"
     )
 
 
@@ -277,6 +280,38 @@ def _search_and_sign(search: ItemSearch) -> ItemCollection:
     return sign(search.get_all_items())
 
 
+@sign.register(collections.abc.Mapping)
+def sign_reference_file(references: Mapping) -> Mapping:
+    """
+    Sign a Kerchunk-style dictionary of references.
+
+    Args:
+        references (Mapping): The dictionary containing the references.
+
+    Returns:
+        references (Mapping): The dictionary, now with signed URLs.
+
+    This method will sign all of the URLs under the ``"templates"`` key. Mappings
+    with other keys will be returned unchanged. See https://fsspec.github.io/kerchunk/
+    for more.
+    """
+    # TODO(python3.8): Use TypedDict instead of Mapping to limit the kinds we accept.
+    # If we accept other mapping types in the future, we'll need to dispatch within
+    # the function.
+    if set(references) == {"version", "templates", "refs"}:
+        references = copy.deepcopy(references)
+
+        for k, v in references["templates"].items():
+            references["templates"][k] = sign_url(v)
+
+    else:
+        raise TypeError(
+            "When providing a mapping, the keys should be 'version', 'templates', "
+            "and 'refs'."
+        )
+    return references
+
+
 def get_token(account_name: str, container_name: str) -> SASToken:
     """
     Get a token for a container in a storage account.

planetary_computer/version.py

@@ -1,3 +1,3 @@
 """Library version"""
 
-__version__ = "0.4.4"
+__version__ = "0.4.5"

setup.cfg

@@ -1,6 +1,6 @@
 [metadata]
 name = planetary-computer
-version = 0.4.4
+version = 0.4.5
 license_file = LICENSE
 author = microsoft
 author_email = planetarycomputer@microsoft.com

tests/data-files/sample-reference-file.json

@@ -0,0 +1,9 @@
+{
+    "version": 1,
+    "templates": {
+        "a": "https://nasagddp.blob.core.windows.net/nex-gddp-cmip6/NEX/GDDP-CMIP6/ACCESS-CM2/historical/r1i1p1f1/hurs/hurs_day_ACCESS-CM2_historical_r1i1p1f1_gn_1950.nc",
+        "b": "https://nasagddp.blob.core.windows.net/nex-gddp-cmip6/NEX/GDDP-CMIP6/ACCESS-CM2/historical/r1i1p1f1/hurs/hurs_day_ACCESS-CM2_historical_r1i1p1f1_gn_1951.nc"
+    },
+    "refs": {
+    }
+}

tests/test_signing.py

@@ -1,4 +1,5 @@
 import os
+import json
 import unittest
 from urllib.parse import parse_qs, urlparse
 from pathlib import Path
@@ -57,6 +58,12 @@ def get_sample_item_collection() -> ItemCollection:
     return ItemCollection([get_sample_item()])
 
 
+def get_sample_references() -> dict:
+    with open(os.fspath(HERE.joinpath("data-files/sample-reference-file.json"))) as f:
+        references = json.load(f)
+    return references
+
+
 class TestSigning(unittest.TestCase):
     def assertRootResolved(self, item: Item) -> None:
         root_link = item.get_root_link()
@@ -180,6 +187,22 @@ class TestSigning(unittest.TestCase):
         result = pc.sign(vrt_string)
         self.assertGreater(result.count("?st"), 0)
 
+    def test_sign_references_file(self) -> None:
+        references = get_sample_references()
+        result = pc.sign(references)
+        for v in result["templates"].values():
+            self.assertSigned(v)
+
+    def test_sign_other_mapping_raises(self) -> None:
+        with self.assertRaisesRegex(TypeError, "When providing a mapping"):
+            pc.sign({"version": None})
+
+        with self.assertRaisesRegex(TypeError, "When providing a mapping"):
+            pc.sign({})
+
+        with self.assertRaisesRegex(TypeError, "When providing a mapping"):
+            pc.sign({"version": None, "templates": None, "refs": None, "extra": None})
+
 
 class TestUtils(unittest.TestCase):
     def test_parse_adlfs_url(self) -> None: